Experimental Study on Strength and Frost Return of Red Mud Unburned Brick

Abstract

The comprehensive utilization of red mud had become a common problem in alumina industry. This paper presented a method for preparing red mud non burning cementitious material without frost return. The red mud from an aluminum oxide plant in Guizhou was used as the research object, and the effects of excitation time on compressive and flexural strength were investigated. The better compressive and flexural strength were obtained when the excitation time was 6h. The compressive strength were 15.62Mpa, 18.55Mpa and 15.6Mpa respectively, and the flexural strength were 2.86Mpa, 3.58Mpa and 3.54Mpa respectively when they were mainted for 7 days, 28 days and immersion for 24 hours, which met the strength requirements of MU15. The sodium in red mud was transformed into stable sodium aluminum hydroxysilicate Al3Na4(OH)(SiO4)3 phase finally, and the concentration of Na+ in the leaching solution extracted by horizontal shaking method was about 370mg/L, so it would not cause frost return to the non burning cementitious material. This study would open up a new way for the mass consumption of red mud.